The invention relates to the design of silicon VLSI circuits. More specifically, it relates to the scheme of control and power supply of silicon VLSI circuits.
Conventional Very Large Scale Integration (VLSI) circuits are driven by electrical signals and power supplies to perform designed functions, controls, and signal transfer. Optical power can be used as a supply source by means of certain devices, such as solar cells, or photovoltaic cells made of amorphous silicon or III-V elements [Y. Liu et al., xe2x80x9cOptically powered optical interconnection systemxe2x80x9d, IEEE Photonics Technology Letters, Vol. 1, no. 1, January 1989, pp 21-23]. Such devices, due to the limitations of semiconductor material, surface required and fabrication process, are not technologically compatible with highly compact VLSI circuits.
In U.S. Pat. No. 4,523,217, Jibu describes a solar powered circuit with CMOS and bipolar transistors. The solar cell provides a reference voltage to the base of the first bipolar transistor and a constant voltage circuit is provided in the substrate. In U.S. Pat. No. 4,701,646, Richardson describes using a photodiode for biasing or level-shifting.
However, little work has been reported on the design of optically controlled and simultaneously optically supplied VLSI circuits implementable in a CMOS process. CMOS is the type of technology used for most of the electronic circuits designed.
Moreover, since it is essential to keep up with the fast advances in technology, there is a need to develop VLSI circuits and systems without dedicated electrical power supply. There is also a need to efficiently solve problems of power distribution, interconnection, control, and interfacing in VLSI circuits.
Accordingly, an object of the present invention is to develop electrical-supply-free circuits and systems.
Another object of the present invention is to adjust voltage levels and produce large on-chip voltages without dissipating electrical power.
Yet another object of the present invention is to implement logic functions, optical and/or electrical signal routing and switching, as well as optical timing in digital CMOS circuits.
According to a first broad aspect of the present invention, there is provided a circuit comprising: a first semiconductor device having at least a first current terminal, a first input voltage terminal, and a first common terminal, said semiconductor device having a voltage between said first input voltage terminal and said first common terminal that controls a current leaving said first current terminal; and a first opto-electronic device having a first anode connected to said first current terminal and a first cathode connected to a ground to convert an input of incident light into an electrical signal, said first opto-electronic device having photodiode and photovoltaic cell capabilities; wherein a voltage is set between a node of said first current terminal that is connected to said first anode and said first common terminal.
Preferably, the circuit comprises a voltage booster module to set the input voltage of the semiconductor device at a biasing level.
According to a second broad aspect of the present invention, there is provided a method for controlling an electrical-supply-free integrated circuit, the method comprising: injecting optical energy into an opto-electronic device connected to a semiconductor device to supply power and act as an input; lowering a voltage at a node of the opto-electronic device and the semiconductor device to substantially zero by removing the injection of the optical energy into the opto-electronic device; lowering a voltage at the node to substantially zero by applying an electrical signal to set the semiconductor device in its on-state; raising a voltage at the node to a high level distinguished from zero volts by injecting optical energy into the opto-electronic device and applying an electrical signal to set the semiconductor device in its off-state.
According to a third broad aspect of the present invention, there is provided a method for locally powering multiple circuit elements on an integrated circuit using light, the method comprising: providing an opto-electronic device for each of the multiple circuit elements on the integrated circuit; projecting light onto a surface of the integrated circuit, each of the opto-electronic device converting the light into a voltage; using the voltage to supply power to the multiple circuit elements on the integrated circuit; wherein no power line is present on the integrated circuit for the multiple circuit elements.
According to a fourth broad aspect of the present invention, there is provided a method for selectively activating a plurality of groups of circuits interconnected on an integrated circuit chip using light, the method comprising: providing an opto-electronic power source means for each of the plurality of groups of circuits; selectively powering at least one of the groups of circuits by projecting the light onto selected ones of the opto-electronic means in order to define a function of the integrated circuit chip.